Public Class Form3
    Inherits System.Windows.Forms.Form

         'Snip

	Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
		Dim frm As New Form4
		frm.ShowDialog()
		DoWhatYouWantWith(frm.Selection)
	End Sub
End Class


Public Class Form4
	Inherits System.Windows.Forms.Form

         'Snip

	Public ReadOnly Property Selection() As Something
		Get
			Return WhateverTheUserSelected
		End Get
	End Property

End Class

		If OpenFileDialog1.ShowDialog = DialogResult.OK Then
			Dim fs As New IO.FileStream(OpenFileDialog1.FileName, IO.FileMode.Open)
			'Do something
			fs.Close()
		End If

Public Class formMain
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "
    Private Sub formMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        rtbTextBox.Enabled = False

    End Sub

    Private Sub mnuNew_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuNew.Click
        ' Make File New Form Show
        Dim formFileNew As formFileNew
        formFileNew = New formFileNew
        formFileNew.ShowDialog()
        rtbTextBox.Enabled = True
        rtbTextBox.Text = formFileNew.txtFileName.Text & formFileNew.optCustom.Checked & formFileNew.optHTML.Checked

    End Sub

End Class

Public Class formFileNew
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Private Sub cmdOk_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdOk.Click
        Me.Close()
    End Sub

    Private Sub cmdCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdCancel.Click
        Me.Close()
    End Sub

End Class